Mechanisms involved in biocontrol and plant induced resistance by Trichoderma asperellum（ T. harzianum T-203）

Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderma spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants.     

双功能木霉突变菌株的筛选和功能分析

研究从木霉菌REMI突变株中筛选到16株对氰化物具有明显降解活性,将其与5种常见病原菌对峙培养,得到7株拮抗性较高的突变株。对这7株转化子进行盆栽试验表明:多数供试转化子对黄瓜幼苗枯萎病具有明显的防效,其中转化子TkA8的防治效果最好,达到了73.5%。同时研究发现TkA8处理黄瓜幼苗可诱导防御反应相关酶系PAL、POD活性明显增加,分别为对照的3.21和4.25倍。因此TkA8是一种具有防病和生物修复氰化物污染的较理想的多功能木霉菌株。     

Novel understanding of Trichoderma interaction mechanisms

Trichoderma- based biofungicides are a reality in commercial agriculture, with more than 50 formulations registered worldwide as biopesticides or biofertilizers. Several research strategies have been applied to identify the main genes and compounds involved in the complex, three-way interactions between fungal antagonists, plants and microbial pathogens. Proteome and genome analyses have greatly enhanced our ability to conduct targeted and genome-based functional studies. We have obtained repr…     

Genetic improvement of Trichoderma ability to induce systemic resistance

The beneficial applications of Trichoderma spp. in agriculture include not only the control of plant pathogens, but also the improvement of plant growth, micronutrient availability, and plant tolerance to abiotic stress. In addition, it has been suggested that these fungi are able to increase plant disease resistance by activating induced systemic resistance (ISR) . The mode of action of these beneficial fungi in the Trichoderma -plant-pathogen interaction are many, complex and not comple…     

The Trichoderma-plant interaction is mediated by avirulence proteins produced by this fungus

The molecular basis of Trichoderma -plant interaction is very complex and still not completely understood. The colonization of the root system by rhizosphere competent strains of Trichoderma results in increased development of root/aerial systems, in improved yields and in plant disease control. Other beneficial effects, such as the induction of plant systemic resistance, have also been described. To understand the mechanisms involved we are using different approaches, including the making…     

Mechanisms involved in biocontrol and plant induced resistance by Trichoderna asperellun (T. harzianum T-203)

Growing awareness of the environmental damage caused by the use of chemical substances for plant disease control in agriculture has raised the need to study biological alternatives, such as activating the defense response of plant crops by inducers not toxic to the environment. Trichoderna spp. are effective biocontrol agents for a number of soilborne pathogens, and are also known for their ability to enhance plant growth and to induce systemic resistance (ISR) in plants.     

Identification of novel Trichoderma hamatum genes expressed during mycoparasitism

Trichoderma species are currently used as biocontrol agents for crop diseases caused by a number of fungal plant pathogens. However, their biocontrol performance in the field can be unreliable and it is likely that more consistent performance could be achieved through knowledge and manipulation of the genes involved. For example, induction of the genes could be optimised for variable environmental and physiological conditions, superior strains could be selected more effectively and novel st…     

Effects of abiotic stress and hormones on the expressions of five13-CmLOXs and enzyme activity in oriental melon(Cucumis melo var.makuwa Makino)

Lipoxygenases(LOXs) are a group of non-heme,iron-containing enzymes and extensively involved in plant growth and development,ripening and senescence,stress responses,biosynthesis of regulatory molecules and defense reaction.In our previous study,18 LOXs in melon genome were screened and identified,and five 13-LOX genes(CmLOX08,CmLOX10,CmLOX12,CmLOX13 and CmLOX18) were predicted to locate in chloroplast.Phylogenetic analysis result showed that the five genes have high homology with jasmonic acid(JA) biosynthesis-related LOXs from other plants.In addition,promoter analysis revealed that motifs of the five genes participate in gene expression regulated by hormones and stresses.Therefore,we analyzed the expressions of the five genes and LOX activity in leaves of four-leaf stage seedlings of oriental melon cultivar Yumeiren under abiotic stress:wounding,cold,high temperature and hydrogen peroxide(H_2O_2),and signal molecule treatments:methyl jasmonate(MeJA),abscisic acid(ABA) and salicylic acid(SA).Real time qPCR revealed that wounding and H_2O_2 induced the expressions of all the five genes.Only CmLOX08 was induced by cold while only CmLOX13 was suppressed by high temperature.ABA induced the expressions of CmLOXIO and CmLOX12 while inhibited CmLOX13 and CmLOX18.MeJA increased the 3 genes expressions except CmLOX08 and CmLOX13,whereas SA decreased the effect,apart from CmLOX12.All the abiotic stresses and signal molecules treatments increased the LOX activity in leaves of oriental melon.In summary,the results suggest that the five genes have diverse functions in abiotic stress and hormone responses,and might participate in defense response.The data generated in this study will be helpful in subcellular localization and transgenic experiment to understand their precise roles in plant defense response.     

拮抗木霉菌的生防机制研究进展

从拮抗木霉菌的抑茵作用机理、诱导抗病性、促进植物生长等方面对木霉菌生防机制的研究进行了综述,并对其应用前景进行了概括。从生防功能的多样性来看,木霉菌是一种理想的生防菌株和难得的生防资源。     

Genetic regulation of conidiation in Trichoderma hamatun

Achieving a balance between vegetative growth and spore production is essential for successful biocontrol by fungi. Low sporulation rates in the field can result in poor establishment and survival,whereas failure of conidia to recognise hosts can lead to persistence without efficacy. Commercial biocontrol products involve bulk preparations of conidia, however considerable variability in conidiation rates exists between biocontrol agents, which can restrict choice of strain for production. The majority of studies on Trichoderma conidiation have focused on the species T. viride and T. atroviride.These species form conidia in response to blue and near-UV light and/or nutrient deprivation and conidiation proceeds in a highly co-ordinated fashion, however relatively little is known on the genetic basis of Trichoderrma conidiation. In addition, whilst photoconidiation appears to be a general response detailed studies in other Trichoderma species are absent. In this study, conidiation in the lesser known biocontrol species T. hamatum is being investigated using a combined morphological and molecular approach. In contrast to T. atroviride, conidiation in response to blue-light was weaker and variable and suggested that additional triggers may be required for the T. hamatum photoresponse. A series of comparative photoconidiation assays are currently being undertaken investigating the effect of inoculum type and abiotic factors on timing and intensity of the response.Results will be discussed in relation to the current knowledge on conidial morphogenesis in Trichoderma. In addition to these morphological assays, a selection of genes implicated in sporulation and the blue-light responses are currently being isolated and characterised from T. hamatum. Two genes, phr1 and cmp1 , which were isolated previously from T. atroviride will be used as early and late markers of gene expression during the photoresponse in T. hamatum in order to define time points for harvesting comparable stage-specific RNA from T. hamatum and T. atroviride. Using degenerate PCR putative sporulation gene orthologues have also been identified in T. hamatum.Work is currently underway to isolate genomic clones of these genes from T. hamatum and T.atroviride. Sequence and expression analysis of orthologues, including expression in response to abiotic factors will be presented and discussed in relation to the current knowledge of the molecular basis of conidiation in Trichoderma and other filamentous fungi.……     

Vision and development in Trichoderma atroviride

Phototropism, the induction of carotenogenesis and reproductive structures, and resetting of the circadian rhythm are controlled by blue light. Trichoderma is used as a photomorphogenetic model due to its ability to conidiate upon exposure to light. In total darkness, T. atroviride grows indefinitely as a mycelium provided that nutrients are not limiting. However, nutrient deprivation and light trigger the conidiation process. A pulse of blue light given to a radially growing colony induc…     

Applications of Trichoderma formulations in crop protection

The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic cap…     

木霉生防菌对大豆幼苗的促生作用及对根腐病的防治效果

[目的]研究木霉菌对大豆幼苗的促生作用及对根腐病的防治效果。[方法]用6株木霉菌剂处理土壤进行盆栽试验,测定大豆植株的形态指标及根腐病的发生情况。[结果]供试木霉菌株均能促进大豆植株生长,其株高、茎粗、根长、干物质积累均比对照增加。木霉菌株制剂均可减轻根腐病的发生,当浓度为5×108个/g时,防效均在70%以上。不同菌株对大豆植株的促生和对根腐病的防治效果不同。[结论]木霉菌能促进大豆的生长和降低根腐病的发生。     

Variations on conserved signaling pathways in biocontrol and development:G protein and MAPK genes of Trichoderma. atroviride and T. virens

Filamentous fungi employ conserved eukaryotic signaling pathway to detect and respond to environmental signals, including the presence of the host. Genetic experiment in which a particular signaling protein is lost, or its activity enhanced, have defined some of the function of heterotrimeric G proteins and MAP kinases in development and virulence. A hallmark of these studies is that orthologs in different species may have different functions. Antagonistic fungal-fungal interactions form …     

植物系统性获得抗性及其信号转导途径

 植物系统获得抗性 (SAR) ,是植物受到病原菌侵染后所激发的一种防卫反应。这种反应由植物抗病基因 (R)与病原菌无毒基因 (avr)的相互识别开始 ,由R基因下游的一些基因整合不同的抗病信号 ,通过水杨酸 (SA)将抗病信号传递下去。这一信号途径在SA下游受非诱导免疫 (NIM/NPR)基因的调控 ,激活NPR1可诱导病程相关蛋白 (PR)基因的表达 ,最终建立具有广谱抗性的SAR。SAR信号途径也可由模拟自然信号的化学物质激活 ,这些激活剂的应用是发展绿色化学农药的新思路。     

Advances in biocontrol mechanism and application of Trichoderma spp. for plant diseases

Trichoderma spp.is a filamentous soil fungus known as an effective biocontrol agent of a range of important airborne and soilborne pathogens,it has universal distribution and economic importance.This article reviewed the researches on biocontrol mech- anism for plant diseases and application of Trichoderma spp.,especially Trichoderma harzianum in recent years.     

绿色木霉菌T23发酵液对番茄几种防御酶活性的影响

应用改良后的GPF培养基,采用3级发酵和固液两相发酵相结合的培养方法培养得到绿色木霉发酵液,研究不同浓度发酵液对番茄幼苗几种防御酶活性的影响.研究结果表明,经发酵液处理的番茄体内与抗性反应相关的苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)、多酚氧化酶(PPO)及超氧化物歧化酶(SOD)活性有明显增加,显示了木霉在促进植物生长方面的潜能.     

New advances in the science and use of Trichoderma spp.

Trichoderma spp. have been known for their strong abilities to produce extracellular enzymes, especially cellulases and glucanases by T. reesei, and also for their abilities to control plant pathogens. Most notably, a number of lines of evidence indicate that the agriculturally relevant strains are synergistic plant symbionts. As plant symbionts they possess the following characteristics: (a) they infect plant roots but cause the plant to restrict their growth to outer layers of the plant co…     

Functional genomic approach to the study of biodiversitywithin Trichoderma

Trichoderma is a fungal genus of great and demonstrable biotechnological value, but its genome is poorly surveyed compared with other model microorganisms. Due to their ubiquity and rapid substrate colonization, Trichoderma species have been widely used as biocontrol organisms for agriculture, and their enzyme systems are widely used in industry. Therefore, there is a clear interest to explore beyond the phenotype to exploit the underlying genetic systems using functional genomics tools. Th…